1. Field of the Invention
The present invention relates to computer-aided navigation systems but more particularly to such a system operated from a boat to determine positions in a waterway whether for navigation, dredging, setting of buoys or the like.
2. Description of the Prior Art
Ocean and air navigation has been implemented over the years by a variety of sophisticated radio and radar equipment. Doppler navigation systems using computers will give continuous readings of distances from starting point and to destination as well as present location in latitude and longitude, speed, bearing to destination, side drift and other data of interest. However, in inland waterways and narrow dredged channels positional accuracy must frequently be plus or minus a few feet. Buoys are frequently misplaced or are forced out of position. Channels are not always dredged exactly as indicated on the charts. The equipment and devices used for positional finding in buoy maintenance and dredging varies widely in character and accuracy. Both radar and laser range finding equipment is used as well as traditional surveying devices. Because such waterways are so beset with navigational hazards, larger vessels customarily employ special pilots with continuous familiarity with the waterways being used.